Valve mechanism for rock drills



April 22,- 1930. T. L. MURPHY VALVE MECHANISM FOR ROCK DRILLS Filed Sept. 21, 1928 INV 17101 10 .LMZQ]? I A k J ENTOR HAS A TORNEY "'2 valve, and

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Patented A r; 2 2; 193 0 THOMAS L. MURPHY, or Ensron, PENNSYLVANIA, AssIGnoRTo rNGERsoLn-RAND 7 COMPANY, or JERSEY CITY, new JERSEY, A conrona'rron or NEW JERSEY VALVE" MEcHA Isr/r 1 033001: DRILLS Application filed September 21,1328. Serial No. 307,486.

This invention relatesto rock drills, but more particularly to a-valvemechanism in tended for efliecting the distribution of pres- 7 sure fluid to the-ends of the cylinder; One objectiof'the'invention is to prevent a fluttering action ofthe valve due to the suc tion created by-the pressure fluid flowing over the raised end of the valve to the ends of the cylinder. I a :Other objects will be in part obvious and in part pointed out hereinafter.- 'In the drawings in which is shown a preferred modification of the invention and in which similar reference charactersrefer to similar parts, a

Figurel is alongitudinal sectional elevation of the rock drill having the invention applied thereto, a I 1 Figure 2 is a plan'view of the distributing Figure 3 is a longitudinal side elevation of a plunger used for maintaining the'valve firmly seated in its limiting positions. s

Referring to the drawings, A designates generally a rock drill having a cylinder B in K which/is disposed a reciprocatory hammer piston C. The cylinder B in this instance is provided with a pair of exhaustportsID and E which are controlled by the piston The piston illustrated is provided with a forward extension F which extends slidably through" a front cylinder washerG disposed in the front end of the cylinder toform a closure for a piston chamber H wherein the piston C '35 reciprocatesf Aclosure' isfprovided in this instance for the rearward end of the cylinder 7 in the'form of aback cylinder washer J, said back cylinder washer J being seated in an enlarged bore K in the rearward end of the cyl-.

In the rearward end of the bore K is disposed rotation mechanismcomprising a rifle bar L which extends throughtheback' cylinder washer J and interlo'cks'slidably with the piston O in a well known manner. The rifle 1 bar L has the usual head 0 in which are disposed "spring pressed plungers P which 00- operate with teeth Q of a rotation ratchet R V known in the art to whichthe present invenfor imparting a rotarymovement to the piston and thus also to a workingimplement' against which the'piston is adapted to strike. The rotation ratchet'R encircles the-head O of the rifle bar and in this instance acts as a seat for a back head S disposed within the rearward end of the cylinder B to which it 'may' be secured in any suitable and well known manner. 7 a

The back head 'S is provided with a chamber T in which is disposed a throttle valve U having a central chamber V into which pres'surefluid from a suitable source of supply inay be constantly admitted. The throttle valve U is of'the rotary type and accordingly" has a lever W whereby said throttle valve may be manipulated. In the-wall of the throttle valve U is a port X which, when the throttle valve is in the'open position, registers with apassage'Y leading from the valve chamber T to a supply reservoir 'Z in'- the front end of'the back head S. 7'

Interposed between the back cylinder washer J and the rotation ratchet R is a valve mechanism whereby the distribution'of pressurefluid to the ends of the cylinder is effected, The valve mechanism comprises a valve chest I) having a valve chamber 6 inits front-end and for one sideof which the'back cylinder washer J forms a closure. The valve 7 Y chamber cis in c'onstant'communication with the supply reservoir Z through a supply passage oZ in'the rotation ratchet Rand the valve provided on its transverse median line with a V v fulcrum f whereon said valveis adapted to rock. i The admission of pressure fluid to the v rearward end of the cylinder is effected through a rearward inlet vpassage g in the back cylinder washer J, and the admissionof pressure fluid to the front end of the piston chamber H is effected through a front inlet passage 71, leading through the back cylinder washer J :and through the cylinder B to: the front end of the piston chamber.

The parts thus far described are well tion pertains andare merely referred to briefly in order to insure a better understanding of the advantages of the invention and the manner in which it cooperates with the valve 6 towards obtaining the objects sought.

In accordance with the practice of the invention, the valve chest I) is provided with a pair of plunger chambers j and k which are disposed perpendicularly with respect to the valve chamber 0 and have bores 0 at their front end which opens into the valve chamber 0. Within the plunger chambers y'and is are disposed plunger-s p and grespectively and said plungers have projections'rat their for ward ends which extend slidably through the bores o to enable said plungers to bearv against the wing portions of the valve 6.

The plunger chambers j and 7c are provided attheir. rearward ends with exhaustpassages s of small crosssectional area for the escape of pressure fluid utilized for actuating the plungers, and at their front ends with vents t to provide an avenue of escape for any pressure fiuidwhic'h may leak into the plunger chambers forwardly of the plungers.

Preferably the plungers p and g are controlled by thepiston C andto this end a kicker passage u is formed'in the cylinder B to lead from'the piston chamber H rearwardly of the exhaust port to a point intermediate the end of the plunger chamber where it may register with a transverse passage 1; in the plunger 79. The passage fl) in turn communicates witha passage win} the plunger having its outlet opening in the rearward end a of the plunger p.

7 Similarly a kicker passage 00 is formed in the cylinderB to lead from the piston chamber H at a, point forwardly of the exhaust ports to the plunger chamber is. The plunger- 9 in the plunger chamber 7t", like'the plunger p, is also provided with a transverse passage or passages Q) whlch may register with the kicker passage 02 and open into the passage w in the plunger for conveying pressure fluid to the rearward end of the plunger-chamber Z2. 'In the construction shown, a cover is provided for the rearward ends of the plunger chambers jand 7c inthe form of a plate 3/ which also acts as a seat for the rotation ratchet R and the head 0 of the rifle bar.

The operation of the device is as follows:

lVith the throttle valve U-in the position illustrated, pressure fluid may flow through the.

passage Y into the reservoir. Z from whence it willflow through the supply passage d to the valve chamber 0. VViththe valve 6 in the position'illustrated, pressure fluid will flow over the raised or right hand end of the valve, thence through the inlet passage 9 into the rearward end of the piston chamber H to drive the piston C forwardly against the working implement.

After the piston C covers the exhaust ports,

the air in the front end of the piston chamber will be compressed and will flow through the inlet passage h to act against the other end of the valve 6. As the piston C proceeds forwardly, the kicker passage u will be uncovered thereby and pressure fluid will then flow through the kicker passage u and the pas- With the valve reversed in the manner described, pressure fluid will flow over the left hand end of the valve throughthe inlet passage it into the front end of the'piston'chamber H to return the piston to its initial position. As the piston proceeds rearwardly, it vill cover the exhaust ports D and E and the air in the rearward end of the piston chamber H will be compressedto act against the seatedor right hand endof the valve. Continuing rearwardly the piston C will uncover the kicker passage and pressure fluid will then flow through the kicker passage 00 and through'the passages 42 and 40 in the plunger g to depress said plunger and consequently tilt the valve to its initial position. .Following this movement of the plunger g, pressure fluid will flow through the exhaust-passages of the valve chamber 70, but this exhaust from the plunger chamber will be slightly delayed due tothe' restricted area of the passage 8 so that ample pressure will remain in the plunger chamber is to maintain the seated end of the valve 6 firmly against the back cylinder washer J, which acts in this instance as a seat for the valve. This'is advantageous at this period in the cycle of operations since it overcomes the force of the suction created upon the opposite or raised end of the valve by the pressure fluid flowing thereover into the piston chamber.

I claim:

1. In a fluid actuated rock drill, the combination .of a cylinder and a piston, a free exhaust port inthe cylinder controlled by the piston, valvenchest having a valve chamber, inlet passages leading from the valve chamber to the cylinder, an oscillatory plat-e valve in the valve chamber to control the inlet passages, plunger chambers in the valve chest, plungers in the plunger chambers extending into the valve chamber, and piston controlled kicker passages for conveying pressure fluid from the cylinder to the plunger chambers to press said plungers against the valve and hold said valve stationary during the admission of pressure fluid to the ends of the cylinvalve, and kicker passages for conveying 2. In a fluid actuated rock'drill, the com I bination of acylinderand a piston, a free exhaust port in the cylinder controlled by the piston, a valve chest having a valve chamber, inlet passages leading from the valve chamber to the cylinder, an oscillatory plate valve in the valve chamber to control the inlet .passages, plunger chambers in the valve chest, plungers in the plunger chambers extending into the valve chamber, and piston controlled kicker passages for conveying pressure fluid from the cylinder to theyplung er chambers to act against one end of the plungersfor pressing'said plungers against the seated end of thevvalve for holding the valve against fluttering during the admission of pressure fluid into the cylinder. 7

3. In a fluid actuated rock drill, the com-' 'bination of a cylinder and a piston, a free exhaust port in the cylinder controlled by the piston, a valve chest having a valve chams ber, inlet passages leading from the valve chamber to the cylinder, an oscillatory plate 7 valve in the valve chamber to control the inlet passages, plunger chambers'in the valve chest disposed perpendicularly with respect to the valve chamber, plungers in the plunger chambers having stems bearing against the pressure fluid from the cylinder to .the plunger chambers to act against the plungers for throwing-the valve and for holding the valve against the effects of the suction created by the pressure fluid flowing over'the raised portion of the valve. I p

4. In a fluid actuatedrock drill, thecombination of a cylinder and a piston, a free exhaust port in the cylinder controlled by the piston, a valve chest having a valve chamber, inlet passages leading fromthe valve chamber to the cylinder, an oscillatory plate valve-in'the valve chamber to control the inlet passages, plunger chambers in'the valve chest disposed perpendicularly with respect to the valve chamber, plungers in the plunger chambers having stems bearing against the valve, and kicker passages for conveying pressure fluid from the cylinderto the plunger chambers, and passages in the plungers iregisteringwith the kicker passages for conveying pressure fluid to vthe rearward end of the plunger chambers to pressthe plungers 1 against the valve'for throwing the valve and for holding said ,valve against the effects of the suction created bythe pressure fluid flowing over the raised portion of the valve.

. In testimony whereof I have signed this specification.

THOMAS L. MURPHY. 

